Biodegradable polymers have been used to prepare biodegradable polymeric matrices, and these matrices can be associated with, or formed into, implantable medical devices. For example, biodegradable polymers can be used to make a thin coating on the surface of a device. Biodegradable polymers having thermoplastic properties can even be molded or formed into a shape to provide an implantable device having useful structural properties. Use of biodegradable matrices can be advantageous because the polymeric matrix becomes totally degraded in the body and there is no need to perform an explantation procedure.
Implantable articles having biodegradable polymeric matrices can also be used to modulate the delivery of drugs to a patient at the site of implantation. Drug-releasing biodegradable matrices can also be in the form of a coating on a device or in the form of an implantable or injectable article that is formed primarily of the biodegradable polymer. Drug contained within the biodegradable matrix can be generally released or eluted from the matrix after the article has been introduced into the body.
The present invention is directed to hydrophobic derivatives of natural biodegradable polysaccharides having pendent silyl ether groups and biodegradable polymeric matrices formed from these polymers. The polymeric matrices can be formed into or associated with an implantable or injectable medical article The polymers and matrices of the invention have been found to provide one or more of the following: improvements for formation of a polymeric matrix in a desired form, such as a medical device coating, a microparticle, or a medical implant; improvements in biocompatibility, and improvements in degradation properties of a matrix formed from these polymers.